Epidemiological study of congenital heart disease.

A community based survey of congenital heart disease was carried out on a random sample of 11,833 children below 15 years in Delhi, India. Congenital heart disease was diagnosed on clinical history and/or clinical examination. Out of the examined sample, 50 were found suffering from congenital heart disease, giving an overall prevalence of 4.2/1000 (4.6/1000 in boys and 3.7/1000 in girls). The prevalence rate was slightly higher than other studies carried out in the country. The reason is obvious. The present study is community based while other studies were hospital or school based. The type of lesions were similar to those reported from other studies. The lesions in order of frequency were ventricular septal defect (46%), atrial septal defect (18%), patent ductus arteriosus (14%), Fallot's tetrology (10%), aortic stenosis (4%), and pulmonary stenosis (4%). Like other studies ventricular septal defect was the commonest lesion. The prevalence rate was higher in the age group 0-4 years and 5-9 years in boys whereas it was higher in adolescent age group (10-14 years) in girls.

Age- and height-specific reference limits of blood pressure of Indian children.

BACKGROUND: Blood pressure in childhood is the most powerful predictor of hypertension in adults. Norms for blood pressure in children are based on the age- and height-specific distribution of blood pressure in a reference sample of healthy children. METHODS: We performed a cross-sectional survey of school-children in the age group 5 to 14 years in south Delhi and studied the distribution of systolic and diastolic blood pressure in 8293 children (4623 boys and 3670 girls). Blood pressure was measured in all children with a mercury column sphygmomanometer using a standardized technique. The first and the fourth Korotkoff sounds were taken as indicative of the systolic and the diastolic blood pressure, respectively. Height percentiles were computed for the study sample for every one-year sex-pooled group. Multiple linear regression was then performed for every one-year group in order to estimate the 90th and 95th percentiles of systolic and diastolic blood pressure according to percentiles of height. RESULTS: Age and height, but not gender, emerged as the principal determinants of systolic and diastolic blood pressure in multivariable linear regression analyses. Age- and height-specific 90th and 95th percentile values of systolic and diastolic blood pressure were estimated, which enabled us to categorize children into 'normal', 'high normal' and 'high' blood pressure groups. CONCLUSIONS: We present age- and height-specific reference values for blood pressure of Indian children based on a large study sample. The use of these standards should aid the identification of children with high blood pressure.

An epidemiological study of blood pressure in school children (5-14 years) in Delhi.

Distribution patterns of blood pressure were studied in a randomised sample of 10,215 school children (5,709 boys 4,506 girls) in the age group 5-14 years in Delhi. The mean values of systolic and diastolic blood pressure (SBP and DBP) increased with age in both sexes. The cut-off points for high blood pressure were based on average SBP and/or DBP values of 95th percentile or greater for each age. The values for SBP ranged from 70 mm Hg to 140 mm Hg and for DBP from 36 mm Hg to 100 mm Hg for the age group 5-9 years. In the age group 10-14 years, the values for SBP and DBP ranged from 72 mm Hg to 160 mm Hg and from 46 mm Hg to 120 mm Hg, respectively. The prevalence of hypertension (systolic, diastolic or both) was 11.9 percent in boys and 11.4 percent in girls, an insignificant difference. Anthropometric variables like height, weight and body mass index showed positive correlation with systolic as well as diastolic blood pressure but the waist-hip ratio showed negative correlation coefficient with blood pressure. Family history of hypertension in one or both the parents was present in 20.4 percent children with high blood pressure compared to 6.8 percent in normotensives. Family history or diabetes was also significantly higher in hypertensive children (5.4%) than in normotensives (3.1%).

Urban-rural differences in the prevalence of coronary heart disease and its risk factors in Delhi.

A community-based epidemiological survey of coronary heart disease and its risk factors was carried out over the period 1984-87 on a random sample of adults aged 25-64 years: 13,723 adults living in Delhi and 3375 in adjoining rural areas. ECG examination and analysis of fasting blood samples for lipids were performed on subjects with the disease and asymptomatic adults free of clinical manifestations. The overall prevalence of coronary heart disease among adults based on clinical and ECG criteria was estimated at 96.7 per 1000 and 27.1 per 1000 in the urban and rural populations, respectively. Prevalences of a family history of coronary heart disease, hypertension, obesity and diabetes mellitus were significantly higher in the urban than in the rural population, and smoking was commoner among rural men and women. Mean levels of total serum cholesterol and low density lipoprotein cholesterol were higher among urban subjects; the mean level of triglycerides was higher in rural subjects. The proportions with total cholesterol levels > 190 mg/dl were 44.1% and 23.0% in urban and rural men, respectively, and 50.1% and 23.9% among urban and rural women, respectively. High density lipoprotein cholesterol levels < 35 mg/dl were found in 2.2% of urban men and 8.0% of rural men compared with 1.6% and 3.5% among urban and rural women, respectively. An abnormal ECG pattern (Q wave or ST-T changes) in asymptomatic individuals is also considered to be a risk factor for coronary heart disease. In asymptomatic adults, 1.7% of urban men and 1.2% of urban women showed abnormal Q waves compared with 0.3% of rural men and 0.4% of rural women. A higher proportion of asymptomatic women showed ST-T changes in both populations. Rural men and women had higher total calorie and saturated fat intakes than urban subjects. Differences in dietary cholesterol intake were marginal. Sodium intake was greater in urban adults. Average daily consumption of alcohol by urban men was 12.7 ml ethanol compared with 2.4 ml in rural men.

Prevalence and patterns of smoking in Delhi: cross sectional study.

OBJECTIVE: To determine the prevalence and predictors of smoking in urban India. DESIGN: Cross sectional. SETTING: Delhi, urban India, 1985-6. SUBJECTS: Random sample of 13,558 men and women aged 25-64 years. MAIN OUTCOME MEASURES: Smoking prevalence; subjects who were currently smoking and who had smoked > or = 100 cigarettes or beedis or chuttas in their lifetime were defined as smokers. RESULTS: 45% (95% confidence interval 43.8 to 46.2) of men and 7% (6.4 to 7.6) of women were smokers. Education was the strongest predictor of smoking, and men with no education were 1.8 (1.5 to 2.0) times more likely to be smokers than those with college education, and women with no education were 3.7 (2.9 to 4.8) times more likely. Among smokers, 52.6% of men and 4.9% of women smoked only cigarettes while the others also smoked beedi or chutta. Compared with cigarette smokers, people smoking beedi or chutta were more likely to be older and married; have lower education, manual occupations, incomes, and body mass index; and not drink alcohol or take part in leisure exercise. CONCLUSION: There are two subpopulations of smokers in urban India, and the prevention strategy required for each may be different. The educated, white collar cigarette smoker in India might respond to measures that make non-smoking fashionable, while the less educated, low income people who smoke beedi or chutta may need strategies aimed at socioeconomic improvement.

Problems of population based epidemiological surveys.

The author had the opportunity to plan and carry out a community based epidemiological survey of Delhi urban population and rural areas of Gurgaon (Haryana) for estimation of prevalence rates and risk factors for the coronary heart disease and hypertension. Based on the experience of conducting this largest population based epidemiological study in India for coronary heart disease and hypertension, problems in conducting these studies were identified. These are discussed in this paper so that other workers may benefit from this experience.

Dietary profile of adults in an urban & a rural community.

A community based dietary survey was carried out in 906 adults (25-64 yr) from 489 families in Delhi urban population and 275 adults from 196 families in rural population of Gurgaon district (Haryana state). A combination of 24 h recall and weightment method was used to assess the individual dietary intake. Daily average intake of various nutrients was calculated. A higher intake of cereals, milk and milk products and sugar and jaggery and a lower intake of pulses, vegetables, fruits, flesh foods and oils and fats were observed in the rural population. The average total calorie intake was 1,749 kcal in the urban and 1,910 in the rural population. The average intake of carbohydrates and proteins was 257.3 g (59.0 en %) and 54.7 g (12.5 en %) in the urban population compared to 295.6 g (61.9 en %) and 63.0 g (13.2 en %) respectively in the rural group. The fat intake was the lowest in the urban low socio-economic group (45.5 g). The contribution of total fat to energy intake ranged from 24.6 en to 31.2 en per cent in different population groups. The rural group showed higher intake of calcium and iron than the urban population. Intake of retinol was higher in the high socio-economic group (urban) than other population groups. Urban/rural differences were observed in intake of retinol, thiamine, niacin, vitamin C and vitamin E. Daily dietary cholesterol intake was the highest in the urban high socio-economic group (119 mg). The fibre intake was higher in the urban than the rural population (8.0 g vs 7.4 g).

A 5-year follow-up study of hypertension in a rural community.

A follow-up study of hypertension was carried out among adults, in the age group between 25 to 64 years, in a rural population of Gurgaon district, Haryana, five years after an initial community based epidemiological survey of the same population. The progress of 77 out of 98 hypertensives detected at the initial survey could be reassessed. The treatment and severity of hypertension found at the initial survey has been compared with that observed on follow-up. The percentage of cases with blood pressure (BP) controlled on treatment increased from 2.6 percent to 45.4 percent on follow-up. An electrocardiogram could be obtained in 66 out of 77 subjects reexamined and was abnormal in 21 cases (31.8%). The electrocardiographic abnormalities found were: myocardial infarction in one, left ventricular hypertrophy in 5, left ventricular hypertrophy with ischaemic ST-T changes in 6, isolated ST-T abnormalities in 5 and conduction defects or arrhythmias in 4 cases. In a cohort of 1,334 subjects who were normotensive at the initial survey, 19 new cases were detected to have hypertension. The overall annual incidence of hypertension was 2.8/1000 (male: 3.8/1000 and female: 2.4/1000). In these hypertensives, a family history of hypertension was present in 10.5 percent and obesity in 42.1 percent.

An epidemiological study of coronary heart disease in different ethnic groups in Delhi urban population.

A community based epidemiologival survey of coronary heart disease (CHD) was carried out on a random urban sample of 13,560 adults of different ethnic groups in Delhi. CHD was diagnosed either on the basis of clinical history, supported by documentary evidence of treatment in hospital/home or on the ECG evidence in accordance with Minnesota Code. The prevalence rate of CHD on clinical basis per 1000 adults was the highest in Sikhs (47.3), lowest in Muslims (22.8) and identical in Hindus (31.8) and Christians (31.2). The prevalence rate/1000 of silent CHD on the basis of ECG was high in Muslims (89.5) and Sikhs (87.3), low in Christians (25.0) and intermediate in Hindus (60.0). The Sikhs showed the highest prevalence rate of myocardial infarct (MI) (15.5) and angina (AP) (31.8) compared to other communities. The prevalence rate of CHD on clinical basis was higher in males than females in all communities. The prevalence of silent CHD was higher in females in Hindus and Sikhs but in Muslims it was higher in men (94.8) than in women (85.2). The wide variations in prevalence rates of CHD in different ethnic groups cannot be explained satisfactorily on the basis of conventional risk factors and support the multifactorial etiological character of CHD.

What is 'desirable' lipid profile.

The lipid profile of subjects with and without coronary heart disease (CHD) was studied in two epidemiological studies conducted in an urban and rural population. The prevalence of CHD was 96.7/1000 in the urban area and 27.1/1000 in the rural area. The lipid levels of the rural population, with an entirely different life style, was significantly lower compared to the urban normal population. The data suggest that if the prevalence of CHD is to be reduced in the urban population, the desirable levels of lipids should be those obtained in the rural normal population rather than the urban, CHD free, population.

An epidemiological study of obesity in adults in the urban population of Delhi.

The prevalence of obesity and its associations were assessed during a community based epidemiological survey of coronary heart disease on a randomised sample of 13,414 adults in the age group 25-64 years living in urban Delhi. Body Mass Index (BMI) > 25 was considered to be the cut off point for defining obesity. By this criterion, the overall prevalence rate of obesity was 27.8%. Obesity was found to be more common in female subjects (Male--21.3%, Female--33.4%, p < 0.001). Obesity was more frequent in male subjects with lower physical activity compared to those doing heavier physical activity (29.3 vs 17.5%, p < 0.001). Physical activity did not influence the prevalence of obesity in females. Hypertension (24.8 vs 8.2%, p < 0.001) coronary heart disease (5.3 vs 2.4%, p < 0.001) and diabetes mellitus (3.2 vs 1.6%, p < 0.001) were more common in the obese than in the non-obese subjects. Hypercholesterolaemia (65.5 vs 53%, p < 0.001) and hypertriglyceridaemia (73.3 vs 61.1%, p < 0.001) were found to be associated with obesity.

A 3-year follow-up of hypertension in Delhi.

A follow-up study of hypertension was carried out among adults in Delhi 3 years after an initial community-based epidemiological survey of the same population. The treatment and the severity status of 1115 out of 1749 individuals with hypertension detected in the initial survey were compared with those observed in the follow-up. The proportion of treated cases with controlled blood pressure rose from 10.8% to 60.8%. Among the cohort of 3611 subjects aged 25-64 years who were normotensive in the initial survey, 132 new cases of hypertension, were detected. The annual incidence of hypertension was the same in men and women (12.2 per 1000). Diabetes and regular alcohol consumption were significant risk factors for hypertension, being present in 13 and 7 cases, respectively. Electrocardiograms (ECGs) were recorded for 871 of the 1115 cases of hypertension. Abnormal ECGs were exhibited by 307 cases (35.2%), of which 24 (2.7%) had had myocardial infarction, 133 (15.3%) had ischaemic ST-T changes, 54 (6.2%) had left ventricular hypertrophy, and 96 (11.0%) had conduction defects and arrhythmias.

Epidemiological study of hypertension in young (15-24 yr) Delhi urban population.

A community based epidemiological study of hypertension was carried out on a random urban sample of young persons (15-24 yr) of Delhi. Hypertension was defined as systolic blood pressure greater than 140 mmHg and/or a diastolic blood pressure greater than 85 mm Hg or a history of current antihypertensive therapy. Of the 6543 subjects examined, 202 were found to be hypertensive. The overall prevalence rate was 30.9/1000 (male 41.2/1000, female 21.7/1000). Secondary hypertension was present in 4 of the 202 patients. Only 16 patients were aware of the presence of hypertension; of these 6 were on medication. Family history of hypertension was present in 87 subjects (43.1%). Of the 202 hypertensives, 67 were obese and 16 were smokers. The degree of physical activity was identical in the hypertensive and non-hypertensive subjects. Blood samples of 129 of the 202 patients were analysed for lipid levels. High values of total cholesterol were observed in nine.

A 3-year follow-up study of coronary heart disease in Delhi.

A follow-up study of coronary heart disease (CHD) was carried out among adults in Delhi 3 years after an initial community-based epidemiological survey of the same population. A total of 575 of the 814 cases of CHD detected clinically and by electrocardiogram (ECG) in the initial survey took part. On re-examination of the original cohort of 4151 adults who were free of CHD both clinically and by ECG in the initial survey, 245 new cases of CHD were detected - 73 on a clinical basis (21 with myocardial infarction and 52 with angina pectoris) and 172 by ECG (13 with myocardial infarction and 159 with probable CHD based on ST and T changes). The overall incidence of CHD was 19.7 per 1000 (males, 17.3 per 1000; females, 21.0 per 1000). The incidence on a clinical basis was 5.9 per 1000 (males, 6.5 per 1000; females, 5.5 per 1000) compared with 13.8 per 1000 by ECG (males, 10.8 per 1000; females, 15.5 per 1000). Although the incidence of myocardial infarction was higher in men (3.6 per 1000) than women (2.2 per 1000), the incidence of angina pectoris was 36.5% higher in women (18.7 per 1000) than in men (13.7 per 1000). Hypercholesterolaemia and systemic hypertension were the commonest risk factors in the 245 new cases.

Epidemiological study of coronary heart disease in Gujaratis in Delhi (India).

A community based survey of coronary heart disease (CHD) was carried out in Gujarati families settled in Delhi. The number of adults surveyed in the age group 25-64 yr was 1317. CHD was diagnosed either on the basis of clinical history supported by documentary evidence of treatment in the hospital or at home or on ECG evidence in accordance with the Minnesota Code. The prevalence rate of CHD on clinical history was 25.1 (28.2 in males and 22.4 in females) per 1000 adults (25-64 yr). The prevalence rates were slightly lower in Gujaratis than the general Delhi urban population. The prevalence rate based on both clinical history and ECG criteria was estimated at 66.8 as compared to 96.8/1000 in general urban Delhi population. The risk factors for CHD such as socio-economic status, family history, obesity, smoking, physical activity and hypertension were studied. The mean and 5th, 50th and 95th percentile values of blood lipids were also estimated in CHD patients and compared with the control group. Hypertension ranked the leading risk factor. Prevalence rate of CHD was higher in the upper socioeconomic group. The positive correlation of higher levels of serum lipids e.g., total cholesterol, low density lipoprotein cholesterol (LDL-C) and triglyceride with CHD was confirmed.